In the field of producing mulch for landscaping applications, it is highly desirable to produce a mulch with natural, dark color, and good moisture retention properties. It is known that many commonly produced mulches are artificially dyed to imitate natural colors. The dyes used for artifical coloration are known to shed water and/or inhibit water absorption. Furthermore, many of the dyes and emulsions used to artificially color mulch are known to contain ingredients which may be harmful when handled, or when leached into the soil and environment.
The attempt to produce mulch by artifially dying ingredients also incurs the use of specialty equipment, such as screeners, dryers, and the like. The costs of such equipment ranges upwardly from $60,000 to $200,000 and above. Mulch produced with such dyes, emulsions, and equipment adds as much as $4.20 per cubic yard of finished material.
Additionally, many commercially produced mulches contain undesirable ingredients, such as demolition debris, glass, plastic, creosoted wood, wood containing toxic preservatives, and some soil conditioners even contain sewage waste products.
Additionally, because of the manner in which ingredients are handled and processed, many mulches contain weed seeds which are undesirable in a landscaping product.
A superior mulch and soil conditioner will be produced by a process which uses only natural, organic ingredients, has a natural, permanent dark color, has an attractive texture, has good moisture retention properties, is free of toxic materials, is free of weed seeds, is safe for humans, pets, and other living things, and qualifies in any organic certification program.
The present invention embodies all of the aforementioned virtues in production and in the final product. A commonly used method for producing mulch which most closely resembles this invention, Zeager U.S. Pat. No. 4,788,790, is referred to in order to illustrate the drawbacks of that process and the improvements of this invention. In that patent, Zeager recommends, as an ingredient, 20% bark, preferably oak bark. Also, Zeager states a preferred temperature of 65 degrees to 85 degrees F. (18.3 degrees to 29.3 degrees C.) in order to produce the dark color for the mulch. Furthermore, Zeager finds faster processing in the summertime, and forms piles in long and low rows with a total volume ranging between 2800 and 9400 cubic yards. As may be seen from the foregoing, the bark used by Zeager is, of course, differrent than the combination of manure-softwood shavings recommended in the present invention. Also, the low temperature range used by Zeager is much too low to include biological activity as part of the manufacturing process. The recommendation by Zeager to perform his method in summer, avoids a more efficient processing during lower ambient temperatures with the present invention process. Furthermore, the conical shapes recommended in the present invention process accounts for the difference in the quantity of heat generated, 160 degrees to 200 degrees F. (70 degrees to 93 degrees C.) with the present invention, as compared to 65 degrees to 85 degrees F. (18.3 degrees to 29.3 degrees C.) noted by Zeager. Still further, the use of a crater and concentric troughs in the piles recommended in the present invention process, serves to increase the uniformity of saturation of liquid within the piles and proper compaction of the piles, when compared to the Zeager process. Lastly, the present invention produces a final pH value which is "sweet", and this is beneficial when used with many types of landscaping plantings, whereas the same result is not achieved by Zeager.